Incorporating Carboxyl-Functionalized Ionic Liquids into SBA-15 to Construct Ultramicropores for Enhanced Adsorption of Low-Concentration Dichloromethane

The efficient purification and recovery of low-concentration chlorinated volatile organic compounds (Cl-VOCs) have become a critical environmental challenge. Adsorption technology has emerged as a key method for the effective removal of low-concentration Cl-VOCs. In this study, porous ionic liquid (IL) composites [N 1888 ][Suc]@SBA-15 were developed by integrating the porous molecular sieve (SBA-15) with hydrophobic carboxyl-functionalized IL ([N 1888 ][Suc]) for the removal of low-concentration dichloromethane (DCM). Notably, the incorporation of IL at a loading of 50 wt % induced the formation of ultramicropores (<0.7 nm) within the [N 1888 ][Suc]@SBA-15 composites. This pore engineering strategy significantly enhanced the DCM adsorption performance. At 303.15 K and a DCM concentration of 0.19 vol %, the 50 wt % [N 1888 ][Suc]@SBA-15 composite exhibited a DCM adsorption capacity of 54.2 mg·g –1, which was more than three times that of [N 1888 ][Suc]. The superior adsorption performance is primarily attributed to the synergistic effect between the functional groups of the IL and the newly generated ultramicropores. Furthermore, the porous IL composite demonstrated excellent recyclability, underscoring its great potential for sustainable industrial applications.